Method and apparatus for separating solids of different gravities



June 25, F. PARDEE METHOD AND APPARATUS FOR SEPARATING SOLIDS OFDIFFERENT GRAVITIES Filed June 20, 1939 2 Sheets-Sheet 1 INVENTOR.fiA/WKB DEE 2,205,432 METHOD AND APPARATUS FOR SEPARATING SOLIDS OFDIFFERENT GRAVITIES E E D m P F Filed June 20.' 19:59 2 Shets-Sheet 2INVENTOR. [EA NKB: PDE'E Patented June 25, 1940 UNITED STATES DHITHODAND APPARATUS FOR SEPARAT- ING SOLIDS OF DIFFERENT GRAVITIES FrankPardee, Hazleton, Pa., assignor to Anthracite Separator Company,Hazleton, Pa., a corporation of Pennsylvania Application June 20, 1939,Serial No; 280,025 8 Claims. (01. 209 45e) My invention relates to amethod and apparatus for separating solids of different densities orspecific gravities such, for example, as a mixture of coal and slate,and more particularly to improvements on an apparatus of the above typedisclosed in my co-pending Patent 2,199,091, April 30, 1940.

In the method and apparatus described in my co-pending application, themixture of slate and coal or other materials of different densities, issupplied to an inclined surface, a conical surface being shown by way ofexample.

The inclined surface is perforated or otherwise permeable to liquid anda liquid is forced periodically upwardly through the plate buoying upthe material thereon to an extentdepending upon the sizes of theparticles of material and the density thereof. As a result the lightermaterials are buoyed up higher and settle more slowly and, therefore,gradually accumulate on top of a lower layer or stratum of heavierparticles. While stratification is advantageous, the method andapparatus operate satisfactorily without stratification.

As the buoying liquid then flows downwardly over the inclined plate itcarries with it the lighter particles. The heavier particles are movedupwardly by a scraper, for example, a spiral scraper when a conicallyinclined surface is used, which is rotated in such a manner as graduallyto move the lower heavier stratum upwardly to an upper discharge edgeas, for ex-, ample, a central opening in an upwardly inclined conicalsurface. The lighter material overflows with the buoyant liquid into anannular receiving trough in which it is caught and from which it isremoved mechanically while the buoying liquid returns and is againforced upwardly through the inclined plate.

The apparatus of the above application operates efficiently but inlarger sizes Where there is a considerable change in altitude from thelowest to the highest part of the inclined plate and consequently aconsiderable'amount of water over the lower part of the plate, the flowof water may take place considerably above the particles of material onthe plate and thus not to be fully effective in sweeping the lighterparticles over the scraper and downwardly into the receiving trough.

Also in the larger size of apparatus the pulsating movement of thebuoying liquid outwardly through the plate and over the lower edgethereof, and a stopping of this movement, may set up a wave motioninwardly and-outwardly that in certain cases may detract from theeffectiveness of the buoying and moving action of the liquid.

In the present invention, I provide means whereby the flow of buoyingliquid over the inclined surface is rendered more eifectivein its actionon the particles of material to be separated and in which the tendencytoward wave motion of the buoying liquid above the separating plate 'iseliminated.

The invention also provides an improved means for receiving the lighterparticles and separating them from thebuoying liquid to be returned tothe plate.

The various features of my invention are illustrated by way of examplein the accompanying drawings in which Fig. l is a plan View of anapparatus embodying a preferred form of the invention, and

Fig. 2 is a vertical section of the apparatus taken on line 2-2 of Fig.l.

In the accompanying drawings the invention is illustrated as applied toa separator having a conical perforated plate Ill with an inner cen'tral discharge opening ll into which the heavier or denser material,such as slate or rock, isdischarged, and a lower outer edge having, anupstanding'wall [2 over which the lighter material, such as coal, isdischarged.

The wall l2 extends downwardly to form an annular chamber beneath theplate It) and about the central opening or passage II. The wall of thecentral opening ll extends to and is supported on an annular base plate13 on which the wall 12 is supported by an annular ring M. The ring !4is provided with openings and plates l5 that swing inwardly and act asinwardly opening check valves to permit the flow of liquid, or buoyingfluid, inwardly into the annular chamber within the wall l2- The wall I2is enclosed in an outer wall it extending upwardly from the base plate[3 to form an annular chamber about the wall 12.

In the annular chamber between the central discharge passage II and theouter wall l2 there is provided a horizontal vertically movable plate llhaving openings closed by upwardly swinging doors l8 that act asupwardly opening check valves. The plate I! is supported on and movedupwardly and downwardly by a number of vertical rods I!) that extendupwardly through suitable stufiing boxes 29 in the floor or bottom wallIt and are in turn supported by a verticallymovable cross head 2!that'may be moved up and down by a walking beam 22 to which it isconnected by a clevis 23.

As the walking beam or lever 22 tilts in oppo- Site directions on afulcrum 24 it alternately lifts the head 2| and lowers it and. with itrods I9 and plate IT. The upward and downward movement of the plate I!acts as a piston to lift the liquid above the plate I! throughperforations in the plate II) from the upper side of which it flows intothe annular chamber between the walls l2 and I6 while water from thischamber flows past the gates I5 into the space below the plate I'I. Asthe plate I? descends the water below this plate is trapped by thevalves or gates I5 and lifts the gates I8 to flow upwardly into thespace above the plate i'I. 'With each upward movement of the plate I Iwater is forced upwardly through the plate I0 and thence into theannular chamber about the plate, then remains stationary while the platedescends so that there is a periodic upward movement of the water, or

buoying liquid, through the plate.

Material of different or differing specific gravity-is supplied from ahopper 25 above the plate I0 onto an annular distributing ring ormechanism 26 from which it is distributed by a rotating spiral scraper21 in an annular path of distribution between the central and outeredges of. the plate-II], or the spiral scraper 21 may be stationary andthe ring or mechanism 26 may rotate. I i

The material thus supplied is buoyed up by the water forced upwardlythrough the plate I0 by the plate II, the lighter material being buoyedmore than the heavier or denser and settling more slowly, The materialis gradually forced inwardly and upwardly to the center passage oropening I I by means of a spiral scraper 28 closely. fitting the uppersurface of the plate ID and rotated in such a direction as to cause thematerial to be pushed upwardly on the slope of the plate I 0 toward thedischarge opening II. The lighter material, however, is not only buoyedup by the buoying liquid, but is .washed downwardly of the slope as theliquid flows outwardly into the annular space between the walls I2 andI6.

Owing to the slope of the. plate I0, it will be apparent that as shownin Fig. 2, there will be a considerable depth of water at the outer orlower edge of the plate, if the plate be one of large diameter. As theplate I I rises it will cause a rapid circulation of water outwardlyfrom the center part of the plate Illinto the annular channel betweenthe plates I2 and I6 meanwhile giving considerable momentum to the massof water thus moved. When the plate stops or moves downwardly themomentum of the water will carry it outwardly causing it to raise thelevel toward the outer wall It and then surge back and cause waves andpulsations in the water. The increasing depth of the water toward theouter edge of the plate I0 and the back surge of the water both decreasethe tendency of the flowing water to carry the lighter productsdownwardly and over the outer edge of the plate In and thus impair theeffectiveness of the apparatus.

To-overcome the surging of the water and to cause it to flow downwardlyin immediate contact with the plate II] or the material resting thereon,-I provide a number of spiral baflle plates 29, 38, SI and 32 extendingin spaced relation from the outer edge of the plate Ill to the inneredge or'opening thereof. The spiral plate 29 is arranged with its loweredge above or spaced from the upperedge of the scraper 28 so as toprovide a passage therebetween for the downward.

flow of liquid and the particles carried with the liquid. The remainingbaffles 30, 3| and 32, four baffles being shown by way of example, havetheir lower edges spaced from the upper surface of the plate Illsufficiently to permit the passage of solid particles upwardly of theplate and downwardly and to confine the flow of liquid to the spacebetween theplate I 0 and the lower edge of the baffles.

Accordingly, the up-flow of water through the plate It carries theparticles .upwardly and brings the lighter particles toward the top andabove the heavier particles and the out-flow of the water being confinedbetween the plate I0 and the lower edges of the baffles 2932 flows in amore rapid current carrying the lighter particles with it downwardlyover the overflow edge I2. Thus these baflies not only confine the flowof liquid to the upper surface of the plate Ii] but also prevent aninward and outward surge thereof. I

The bafiles 2932 are supported and carried on a number of radial arms 33from which the baffles are suspended. The scraper plates 28 are in turnsupported from the baflie 29 by any suitable means, such as theconnecting bars 34. The arms 33 are suspended from a central shaft 35which may be rotated to move the scrapers 28 over the surface I0. Anyother suitable arrangement may be made whereby the baflles 2932 may besupported above the plate I0. 1

The lighter particles discharged over the up-' per edge of the wall I2fall into an annular trough formed by a bottom 36 and a side wall 31.The arms 33 have depending projections 33 extending downwardly into thetrough so as to carry the particles in the trough around toa dischargechute 39 which delivers them to a conveyor 40 which removes them fromthe annular chamber formed between the walls I2 and I6. The abovearrangement provides ample space for the circulation of the water andenables the discharged particles to be separated from the water and bedelivered in clean washed condition. 1

Through the above apparatus separators of the above type may be made ofany desired size and an effective well-directed circulation of the watermay be provided so as to separate the lighter wardly toward an upperdischarge opening, it will I be understood that this arrangement mightbe plate and rotatable to move material upwardly of said surface, meansto supply material to be separated to said plate, means to circulate abuoying fluid through said plate to buoy lighter material over saidscraper and downwardly .over said surface and spiral members above saidsur-. face and spaced therefrom suificiently to permit downwardly oversaid surface to the lower outeredge and into said channel, spiralmembers above said surface and spaced therefrom sufficiently to permitthe passage of buoyant fluid and buoyed particles thereunder and a fluidreceiving chamber enclosing said annular channel. 1

3. Apparatus of the type described which comprises a conical perforateplate having a central discharge opening and a peripheral dischargeedge, a scraper extending spirally on said conical plate and rotatableto move material upwardly over the surface thereof, means to supply material to be separatedrto said plate, means to circulate a buoying fluidthrough said plate to buoy lighter material over said scraper anddownwardly over said surface and bafile members spaced above saidsurface to permit the passage of buoyant fluid and buoyed particlesthereunder and to speed the flow of fluid over the surface thereof.

4. Apparatus of the type described which comprises a conical perforateplate having a central discharge opening and a peripheral discharge edgeand sloping downwardly from said opening to said edge, a scraperextending spirally on said conical plate and rotatable about the axisthereof to move material upwardly on the surface of said plate, means tosupply material to be separated to said plate in an annular zone betweensaid peripheral edge and said central opening, means to circulate abuoying fluid upwardly through said plate and downwardly over theperipheral edge thereof to buoy lighter material over said scraper tosaid peripheral edge and means above said scraper to regulate the flowof fluid except along the surface of said plate.

5. Apparatus of the type described which comprises a conical perforateplate having an upper central discharge opening and a lower peripheraldischarge edge, a scraper extending spirally on I said conical plate androtatable to move material upwardly on the surface of said plate, meansto supply material to said plate in a zone intermediate its peripheraledge and the central opening, means to circulate a buoying fluid throughsaid plate to buoy lighter material over said scraper and downwardlyover said surface and baille members above said surface and spacedtherefrom to impede the flow of fluid except over the immediate surfaceof said plate, an annular fromv said opening and from said edge to forman annular chamber below said plate, a receiving chamber about the outerof said walls, a piston in said chamber, said piston having upwardlyopening valves, inwardly opening valves below said piston in the wallextending from said periphery, means to move said piston upwardly anddownwardly to circulate fluid intermittently upwardly through said plateto overflow into said outer annular chamber, a scraper arranged spirallyon said plate, means to rotate said scraper to move material'upwardlytoward said central discharge opening and baflle members in the fluidabove said plate to impede radial movement of the fluid, said baiiicmembers being spaced above said plate to permit the passage of fluiddownwardly thereover vin close contact with said plate.

'7. Apparatus of the type described which comprises a conical perforateplate having a centraldischarge opening and .a peripheral discharge edgeand cylindrical walls extending downwardly from said opening and fromsaid edge to form an annular chamber below said plate, a receivingchamber about the outer of said walls, a piston in said chamber, saidpiston having upwardly opening valves, inwardly opening valves belowsaid piston in the wall extending downwardly from said periphery, meansto move said piston upwardly and downwardly to circulate fluidintermittently upwardly through said plate to overflow into said outerannular chamber, a scraper arranged spirally on said plate, means torotate said scraper to move material upwardly toward said centraldischarge opening and bafiie members in the liquid above said plate toimpede radial movement of the liquid, said baiiie members being spacedabove said plate to permit the passage of fluid downwardly thereover inclose contact with said plate and means to supply material to beseparated to said plate in an annular path between said peripheral edgeand said central opening.

8. Apparatus of the type described which comprises a conical perforateplate having a central discharge opening and a peripheral discharge edgeand cylindrical walls extending downwardly from said opening and fromsaid edge to form an annular chamber below said plate, a receiv ingchamber about the outer of said walls, a piston in said chamber, saidpiston having upwardly opening valves, inwardly opening valves belowsaid piston in the wall extending downwardly from said periphery, meansto move said piston upwardly and downwardly to circulate fluidintermittently upwardly through said plate to overflow into said outerannular chamber, a scraper arranged spirally on said plate, means torotate said scraper to move material upwardly toward said centraldischarge opening and bafllemembers in the fluid above said plate toimpede radial movement of the fluid, said baffle mempath between saidperipheral edge and said central opening, an annular channel in saidouter annular chamber toreceive material discharged over said peripheraledge, a conveyor to receive material from said channel and means tosweep material in said channel to said conveyor.

FRANK PARDEE.

